Wire clamp



T. H. ABBIATI Oct. 15, 1963 WIRE CLAMP Original Filed Nov. 4, 1954.

INVENTOR. THEODORE H. ABBIATI @M1/ff ATTORNEY United States Patent Oiilice 3,1%,758 Patented Get. 15, 1963 3,106,758 WIRE CLAMP Theodore H. Abbiati, Denver, Colo., assigner to Screw Machine Products Co., Denver, Colo.

Original application Nov. 4, 1954, Ser. No. 466,883, now Patent No. 2,871,738, dated Feb. 3, 1959. Divided and this application Nov. 4, 1958, Ser. No. 771,894I

1 Claim. (Cl. 24-27) This yapplication is a division of my copending application Serial No. 466,883 filed November 4, 1954, now Patent No. 2,871,738, `which is a continuation-in-part of my prior application Serial No. 179,305 filed August 14, 1950, now abandoned.

The present invention relates to the art of Wire coil clamps. The clamp of this invention is especially useful for binding together in tightly sealed relation an assembly of concentric telescoped members the outer of which is compressible; for example, a hose and coupling fitting of the type lgenerally similar to those shown in U.S. patents Gunn 1,700,043, McKee 1,897,319, Bent 1,982,630 and Conklin 2,600,394. It is useful for many other purposes as well. It provides an eicent servin-g for rope ends, both fiber rope, Wire rope, and stranded wire cable, to prevent the strands from unraveling when severed. lt is useful for holding the joints of telescoped tubing in fixed relation, both lineal and rotary.

The wire clamps employed in the above noted patent assemblies usually consist of a single len-gth of wire formed as a pair of axially spaced and aligned coils each joined by a substantially U-sh'aped bight portion extending from the outermost loop of each coil. The two ends of the length of Wire from which the clamp. is formed extend in parallel from the innermost loop of the coils and through the bight portion for engagement by the pulling means of a tool utilized to apply the clamp in service. Application of such clamps is effected by fastening the bight to a lfixed anchorage carried :by the tool and constricting the clamp coils by operating the tool to pull Kon the parallel terminal ends of the wire. When a desired degree of tightening by such constriction is obtained, the ends of the wire are bent back over the bight as locking hooks and then severed, the cut ends then being hammered down into the surface of the hose to complete the clamp.

In all such arrangements of the types above stated the pulling `force exerted on the wire ends by the applying tool is opposed at all times by an equal and opposite force effective on the bight by reason of its fixed anchorage. Progressive increase in pull acts, therefore, only to constrict the clamp coils down into the stationary surface of the dormant hose under a constantly increasing wire tension that is not distributed uniformly throughout the different portions of each coil of wire comprising the clamp. This non-uniform distribution of tension in each coil is easily understood if it be assumed that each coil has two turns and that each coil is being pulled by equal force from each end. As constriction begins thecenter of each coil, being one full turn from either end, remains stationary. The material derived from the difference between the original circumference of the coils and their final constricted circumference is rdrawn away in both directions from the stationary center of each coil. If now each increment of each turn is considered separately it will be realized that proceeding o'ircumferentially outwards from the stationary center of each coil in either direction towards either end of the clamp the distance traveled around the circumference by such increment during constriction becomes greater and greater as the ends are approached. 'I'he iirst increment next to the stationary center of the coils barely moves around the circumference, and the last increment next to an end of the clamp travels all the length of the material pulled out of that end of the coil. The combined resistance of the assembly against 'being compressed, together With the friction between the `wire and the assembly sliding the wire unequal distances around the circumference, and the snubbing action created by pulling in opposite directions around a full turn each Way from the stationary center of each coil combine to cause an unequal distribution oi tensile and compressive forces in the different increments of the turns lof the coils. This unequal distri-bution of tension sets up stresses and strains in the wire which -automatically relieve themselves in time by resolution of forces; so that the clamp coils loosen after a period of use and seriously impair the elfectiveness of the sea'l. On high pressure lines the eiect can be disastrous. If, however, the tension in the Various parts of the clamp is maintained in a state of equalization uniformly throughout the clamp while the coils are constricting there is no subsequent resolution of forces and the'clamp coils do not loosen. y

I have discovered that tension in a Wire clamp of the character described can 'be equalized uniformly throughout the clamp While its coils are constricting, by both sliding and rolling the excess wire of the clamp circumferentially around and upon the surface of the hose under a progressively increasing tension which constricts the coils and at the same time causes the assembly to rotate concurrently on its axis. The method is claimed in my copending application Serial No. 466,883, now Patent No. 2,871,738, of which this application is a division. One method illustrated therein shows the pulling force exerted on the two Wire ends of a clamp after Ipassing the ends through a xed vertical abutment against which the hose assembly is pulled. This will pinch the unattached elongated bight end between the assembly and the abutment and restrain its movement until preliminary constriction has taken place. It will be apparent that an increased pulling force applied on the Wire ends at a point substantially tangent to the coils, Will be opposed by an equal parallel but oppositely directed force applied where the coils contact the vertical abutment on their horizontal diameter. Since the two opposing forces are not applied through the sa-me point they cause the assembly to rotate While constricting and finally under increasing tension to pull the bight end down and roll its initially excess material into the coils. This action pulls the clamp tight from one side, then mechanically rolls the assembly over and tightens it from the other side, thereby automatically making the tension equal throughout the entire coil. It requires use of a specially designed clamp on which an elongated bight provides surplus wire that is pulled into and through the clam-p coils against a strong but yielding resistance progressively i-ncreased in ratio to the applied pulling force until a predetermined length of the surplus wire is pulled into and through the clamp coils. =In order to be effective in Icqualizing tension throughout the constricting coils their rotation must be s-ubstantial; that` is, in the order of an arc of one hundred and eighty degrees. That cannot be accomplished unless suiicient Wire is fed from the elongated bight into the simultaneously rotating and constricting coils of the clamp to compensate for the wire bein-g pulled out of the coils by the applicator tool.

The primary object of this invention is to provide a wire clamp for binding together in tightly sealed relation by mechanical methods an assembly of concentric telescoped members the outer of which is compressible, which clamp after application will have equal tension throughout all portions of its coils.

A further object of this invention is to provide a mechanical method and a means to automatically equalize the tension throughout the turns of a wire hose clamp; said mechanical method acting to rotate the assembly during constriction by means of the surplus material con` tained in an elongated bight, self-operating and inherent in the structure of the clamp.

Another object is to provide a clamp which from its structure and its manner of constriction will automatically produce uniform tension throughout the turns of its coils without the extra labor` of manually rolling the hose as detailed in the patent to Bent 1,982,630.

A further object of the resent invention is to provide a wire clamp for binding together in tightly sealed relation an assembly of concentric telescoped members the outer of which is compressible, in which clamp a pair of axially spaced constriction coils are connected by an elongated bight portion dimensioned to contain initially surplus wire for winding into the clamp coils incident to their simultaneous constriction and rotation to compensate for wire pulled from the coils in effecting such constriction and rotation.

Another object is to provide a clamp of the character described consisting of a single length of wire formed in a pair of axially spaced coils, with the two terminal ends extended in parallel relation in one direction from the coils substantially tangent thereto and together constituting one clamp end portion, and with an elongated bight joining the coils and extending tangentially therefrom as another clamp end portion, the terminal end portions passing through the bight, and the elongated bight portion containing initially surplus wire of a length predetermined with reference to the number of turns in a coil, its original diameter, its final constricted diameter, and the length of the bight from its tip to its point of tangency.

Other and incidental objects will be apparent from the following description taken in conjunction with the accompanyin g drawings, in which:

FIG. l is a perspective view of one embodiment of the clamp of this invention;

FIG. 2 is a side elevation thereof;

FIG. 3 is a top plan View.

Clamps constituted in accordance with the present invention are designed for use in the method claimed in my copending application Serial No. 466,883, now Patent No. 2,871,738. The specic form of clamp herein shown and described is illustrative, not restrictive. The invention is capable of expression in specific embodiments other than as shown.

In the specific embodiment of the invention here shown the clamp consists of a single length of appropriate gauge wire formed as a pair of axially aligned coils 26 with the coils spaced axially in parallel relation and joined by a U-shaped elongated bight portion with its tip 27 connecting straight portions 28 which extend tangentially from the outer turns of the coils and which occupy with the tip 27 a common plane. The bight portion, which in its entirety includes the tip 27 and the portions 28, is elongated relative to the coils such that the tip 27 is spaced well beyond the point where the terminal ends 29 of the wire pass through the bight. These terminal ends 29 extend from the inner turns of the coils and pass through the bight in a common plane which crosses the portions 28. This elongated bight contains wire which, after the clamp becomes partially constricted in application, will be wound into the coils during their simultaneous constriction and rotation to compensate for the wire that is being pulled from the coils in etecting such constriction and rotation. This mechanically equalizes the tension throughout all portions of the turns of the coils and is new to the art.

Although in the embodiment here illustrated the terminal end portions 29 of the wire pass through the bight portion in a plane substantially perpendicular to the plane of the bight portion, it is within the purview of this invention and it is so intended that the terminal end portions 29 and the bight portion may cross each other in any other angular relationship or may cross each other in a single plane common to both. The essential feature of this invention is that the bight portion must extend suiiciently beyond the underlying terminal end portions 29 to provide initially suhcient wire to be rolled into the coils to replace the wire drawn from the coils by the pulling means of the tool by which the clamp is applied in service and thereby mechanically force the assembly to rotate and equalize the tensions throughout the coils.

In the clamp of this invention the point of nal constriction of the coils is reached when the tip of the bight seats upon the terminal end portions 29 of the wire and all surplus material has been drawn from the coils. Due to standardization of hose sizes and gauges of wire it is possible in the present invention to predetermine, for any particular hose size and type, the length of wire that should be in the bight portion initially in order to achieve maximum eliiciency of the clamp when applied, having regard to the original diameter of coil and a desired linal diameter of constriction. It can be determined from the following equation:

where T is the number of turns in a coil, D1 is the original diameter of the clamp coil, D2 is the nal constricted diameter of the coil, S is all of the wire that is pulled by the free ends or" the clamp out of each of the original coils of the clamp plus the wire that is drawn out of the elongated bight while the clamp is constricting, and LB is the length of the bight from its tip to its point of tangency. This length is so proportioned that when the initially excess wire is drawn out of the bight, wound into and around the coils and a corresponding length added to the length of wire derived from the constriction of the coils while both lengths are consecutively being pulled cireumferentially around the assembly in the same direction they will collectively produce a mechanical rotation of the assembly of at least and thereby equalize the tension throughout all portions of the turns in the coils of the clamp.

From the preceding description it will be seen that the clamp consists of a single length of wire bent initially intermediate its ends in U-shape to provide an elongated bight with spaced parallel arms. The tip of the elongated bight constitutes one end of the clamp and the free ends of the arms constitute the other end of the clamp. Each arrn intermediate its free end and the bight is formed in a pair of coils.

I claim:

A clamp for binding together in tightly sealed relation an assembly of concentric telescoped members the outer of which is compressible, consisting or" a length of wire having intermediate its ends a U-shaped bight providing one end of the clamp and having in each arm of the bight axially aligned coils whose free ends pass in parallel relation through the bight and together constitute the other end of the clamp, both ends of the clamp being substantially tangent to the coils; the bight having a length from its tip to its point of tangency so proportioned that when the initially excess wire is drawn out of the bight, wound into and around the coils and a corresponding length added to the length of wire derived from the constriction of the coils while both lengths are consecutively being pulled circumferentially around the assembly in the same direction they will collectively produce a mechanical rotation of the assembly of at least 180 and thereby equalize the tension throughout all portions of the turns in the coils of the clamp, the length of wire in each arm of the bight between its tip and its point of tangency constituting initially wire of a length predetermined by the following equation:

sT(D1-D2)=LB Where T is the number of turns in a coil, D1 is the original diameter of the clamp coil, D2 is the final constricted diameter of the coil, S is all of the wire that is pulled by the free ends of the clamp out of each of the original coils of the clamp plus the wire that is drawn out of the elongated bight while the clamp is constricting, and LB is the length of the bight from its tip to its point of tangency, this length is so proportioned that when the initially excess Wire is drawn out of the bight, wound into and around the coils and a corresponding length added to the length of wire derived from the constriction of the coils While both lengths are consecutively being pulled circumferentially around the assembly in the same direction they will collectively produce said mechanical rotation of the assembly and thereby equalize the tension throughout all portions of the turns in the coils of the clamp.

References Cited in the file of this patent UNITED STATES PATENTS 

